Due to the increasing need of highly dependable services in Service-Oriented Architectures (SOA), service-level agreements include more and more frequently such traditional aspects as security, safety, availability, reliability, etc. Whenever a service can no longer be provided with the required QoS, the service requester need to switch dynamically to a new service having adequate service parameters. In the current paper, we propose a metamodel to capture such parameters required for reliable messaging in services in a semi-formal way (as an extension to [1]). Furthermore, we incorporate fault-tolerant algorithms into appropriate reconfiguration mechanisms for modeling reliable message delivery by graph transformation rules.